    #!/bin/bash

    # Tetris Game
    # 10.21.2003 xhchen<[email]xhchen@winbond.com.tw[/email]>

    #APP declaration
    APP_NAME="${0##*[\\/]}"
    APP_VERSION="1.0"


    #颜色定义
    cRed=1
    cGreen=2
    cYellow=3
    cBlue=4
    cFuchsia=5
    cCyan=6
    cWhite=7
    colorTable=($cRed $cGreen $cYellow $cBlue $cFuchsia $cCyan $cWhite)

    #位置和大小
    iLeft=3
    iTop=2
    ((iTrayLeft = iLeft + 2))
    ((iTrayTop = iTop + 1))
    ((iTrayWidth = 10))
    ((iTrayHeight = 15))

    #颜色设置
    cBorder=$cGreen
    cScore=$cFuchsia
    cScoreValue=$cCyan

    #控制信号
    #改游戏使用两个进程，一个用于接收输入，一个用于游戏流程和显示界面;
    #当前者接收到上下左右等按键时，通过向后者发送signal的方式通知后者。
    sigRotate=25
    sigLeft=26
    sigRight=27
    sigDown=28
    sigAllDown=29
    sigExit=30

    #七中不同的方块的定义
    #通过旋转，每种方块的显示的样式可能有几种
    box0=(0 0 0 1 1 0 1 1)
    box1=(0 2 1 2 2 2 3 2 1 0 1 1 1 2 1 3)
    box2=(0 0 0 1 1 1 1 2 0 1 1 0 1 1 2 0)
    box3=(0 1 0 2 1 0 1 1 0 0 1 0 1 1 2 1)
    box4=(0 1 0 2 1 1 2 1 1 0 1 1 1 2 2 2 0 1 1 1 2 0 2 1 0 0 1 0 1 1 1 2)
    box5=(0 1 1 1 2 1 2 2 1 0 1 1 1 2 2 0 0 0 0 1 1 1 2 1 0 2 1 0 1 1 1 2)
    box6=(0 1 1 1 1 2 2 1 1 0 1 1 1 2 2 1 0 1 1 0 1 1 2 1 0 1 1 0 1 1 1 2)
    #所有其中方块的定义都放到box变量中
    box=(${box0[@]} ${box1[@]} ${box2[@]} ${box3[@]} ${box4[@]} ${box5[@]} ${box6[@]})
    #各种方块旋转后可能的样式数目
    countBox=(1 2 2 2 4 4 4)
    #各种方块再box数组中的偏移
    offsetBox=(0 1 3 5 7 11 15)

    #每提高一个速度级需要积累的分数
    iScoreEachLevel=50        #be greater than 7

    #运行时数据
    sig=0                #接收到的signal
    iScore=0        #总分
    iLevel=0        #速度级
    boxNew=()        #新下落的方块的位置定义
    cBoxNew=0        #新下落的方块的颜色
    iBoxNewType=0        #新下落的方块的种类
    iBoxNewRotate=0        #新下落的方块的旋转角度
    boxCur=()        #当前方块的位置定义
    cBoxCur=0        #当前方块的颜色
    iBoxCurType=0        #当前方块的种类
    iBoxCurRotate=0        #当前方块的旋转角度
    boxCurX=-1        #当前方块的x坐标位置
    boxCurY=-1        #当前方块的y坐标位置
    iMap=()                #背景方块图表

    #初始化所有背景方块为-1, 表示没有方块
    for ((i = 0; i < iTrayHeight * iTrayWidth; i++)); do iMap[$i]=-1; done


    #接收输入的进程的主函数
    function RunAsKeyReceiver()
    {
            local pidDisplayer key aKey sig cESC sTTY

            pidDisplayer=$1
            aKey=(0 0 0)

            cESC=`echo -ne "\033"`
            cSpace=`echo -ne "\040"`

            #保存终端属性。在read -s读取终端键时，终端的属性会被暂时改变。
            #如果在read -s时程序被不幸杀掉，可能会导致终端混乱，
            #需要在程序退出时恢复终端属性。
            sTTY=`stty -g`

            #捕捉退出信号
            trap "MyExit;" INT TERM
            trap "MyExitNoSub;" $sigExit

            #隐藏光标
            echo -ne "\033[?25l"


            while :
            do
                    #读取输入。注-s不回显，-n读到一个字符立即返回
                    read -s -n 1 key

                    aKey[0]=${aKey[1]}
                    aKey[1]=${aKey[2]}
                    aKey[2]=$key
                    sig=0

                    #判断输入了何种键
                    if [[ $key == $cESC && ${aKey[1]} == $cESC ]]
                    then
                            #ESC键
                            MyExit
                    elif [[ ${aKey[0]} == $cESC && ${aKey[1]} == "[" ]]
                    then
                            if [[ $key == "A" ]]; then sig=$sigRotate        #<向上键>
                            elif [[ $key == "B" ]]; then sig=$sigDown        #<向下键>
                            elif [[ $key == "D" ]]; then sig=$sigLeft        #<向左键>
                            elif [[ $key == "C" ]]; then sig=$sigRight        #<向右键>
                            fi
                    elif [[ $key == "W" || $key == "w" ]]; then sig=$sigRotate        #W, w
                    elif [[ $key == "S" || $key == "s" ]]; then sig=$sigDown        #S, s
                    elif [[ $key == "A" || $key == "a" ]]; then sig=$sigLeft        #A, a
                    elif [[ $key == "D" || $key == "d" ]]; then sig=$sigRight        #D, d
                    elif [[ "[$key]" == "[]" ]]; then sig=$sigAllDown        #空格键
                    elif [[ $key == "Q" || $key == "q" ]]                        #Q, q
                    then
                            MyExit
                    fi

                    if [[ $sig != 0 ]]
                    then
                            #向另一进程发送消息
                            kill -$sig $pidDisplayer
                    fi
            done
    }

    #退出前的恢复
    function MyExitNoSub()
    {
            local y

            #恢复终端属性
            stty $sTTY
            ((y = iTop + iTrayHeight + 4))

            #显示光标
            echo -e "\033[?25h\033[${y};0H"
            exit
    }


    function MyExit()
    {
            #通知显示进程需要退出
            kill -$sigExit $pidDisplayer

            MyExitNoSub
    }


    #处理显示和游戏流程的主函数
    function RunAsDisplayer()
    {
            local sigThis
            InitDraw

            #挂载各种信号的处理函数
            trap "sig=$sigRotate;" $sigRotate
            trap "sig=$sigLeft;" $sigLeft
            trap "sig=$sigRight;" $sigRight
            trap "sig=$sigDown;" $sigDown
            trap "sig=$sigAllDown;" $sigAllDown
            trap "ShowExit;" $sigExit

            while :
            do
                    #根据当前的速度级iLevel不同，设定相应的循环的次数
                    for ((i = 0; i < 21 - iLevel; i++))
                    do
                            sleep 0.02
                            sigThis=$sig
                            sig=0

                            #根据sig变量判断是否接受到相应的信号
                            if ((sigThis == sigRotate)); then BoxRotate;        #旋转
                            elif ((sigThis == sigLeft)); then BoxLeft;        #左移一列
                            elif ((sigThis == sigRight)); then BoxRight;        #右移一列
                            elif ((sigThis == sigDown)); then BoxDown;        #下落一行
                            elif ((sigThis == sigAllDown)); then BoxAllDown;        #下落到底
                            fi
                    done
                    #kill -$sigDown $$
                    BoxDown        #下落一行
            done
    }


    #BoxMove(y, x), 测试是否可以把移动中的方块移到(x, y)的位置, 返回0则可以, 1不可以
    function BoxMove()
    {
            local j i x y xTest yTest
            yTest=$1
            xTest=$2
            for ((j = 0; j < 8; j += 2))
            do
                    ((i = j + 1))
                    ((y = ${boxCur[$j]} + yTest))
                    ((x = ${boxCur[$i]} + xTest))
                    if (( y < 0 || y >= iTrayHeight || x < 0 || x >= iTrayWidth))
                    then
                            #撞到墙壁了
                            return 1
                    fi
                    if ((${iMap[y * iTrayWidth + x]} != -1 ))
                    then
                            #撞到其他已经存在的方块了
                            return 1
                    fi
            done
            return 0;
    }


    #将当前移动中的方块放到背景方块中去,
    #并计算新的分数和速度级。(即一次方块落到底部)
    function Box2Map()
    {
            local j i x y xp yp line

            #将当前移动中的方块放到背景方块中去
            for ((j = 0; j < 8; j += 2))
            do
                    ((i = j + 1))
                    ((y = ${boxCur[$j]} + boxCurY))
                    ((x = ${boxCur[$i]} + boxCurX))
                    ((i = y * iTrayWidth + x))
                    iMap[$i]=$cBoxCur
            done

            #消去可被消去的行
            line=0
            for ((j = 0; j < iTrayWidth * iTrayHeight; j += iTrayWidth))
            do
                    for ((i = j + iTrayWidth - 1; i >= j; i--))
                    do
                            if ((${iMap[$i]} == -1)); then break; fi
                    done
                    if ((i >= j)); then continue; fi

                    ((line++))
                    for ((i = j - 1; i >= 0; i--))
                    do
                            ((x = i + iTrayWidth))
                            iMap[$x]=${iMap[$i]}
                    done
                    for ((i = 0; i < iTrayWidth; i++))
                    do
                            iMap[$i]=-1
                    done
            done

            if ((line == 0)); then return; fi

            #根据消去的行数line计算分数和速度级
            ((x = iLeft + iTrayWidth * 2 + 7))
            ((y = iTop + 11))
            ((iScore += line * 2 - 1))
            #显示新的分数
            echo -ne "\033[1m\033[3${cScoreValue}m\033[${y};${x}H${iScore}         "
            if ((iScore % iScoreEachLevel < line * 2 - 1))
            then
                    if ((iLevel < 20))
                    then
                            ((iLevel++))
                            ((y = iTop + 14))
                            #显示新的速度级
                            echo -ne "\033[3${cScoreValue}m\033[${y};${x}H${iLevel}        "
                    fi
            fi
            echo -ne "\033[0m"


            #重新显示背景方块
            for ((y = 0; y < iTrayHeight; y++))
            do
                    ((yp = y + iTrayTop + 1))
                    ((xp = iTrayLeft + 1))
                    ((i = y * iTrayWidth))
                    echo -ne "\033[${yp};${xp}H"
                    for ((x = 0; x < iTrayWidth; x++))
                    do
                            ((j = i + x))
                            if ((${iMap[$j]} == -1))
                            then
                                    echo -ne "  "
                            else
                                    echo -ne "\033[1m\033[7m\033[3${iMap[$j]}m\033[4${iMap[$j]}m[]\033[0m"
                            fi
                    done
            done
    }


    #下落一行
    function BoxDown()
    {
            local y s
            ((y = boxCurY + 1))        #新的y坐标
            if BoxMove $y $boxCurX        #测试是否可以下落一行
            then
                    s="`DrawCurBox 0`"        #将旧的方块抹去
                    ((boxCurY = y))
                    s="$s`DrawCurBox 1`"        #显示新的下落后方块
                    echo -ne $s
            else
                    #走到这儿, 如果不能下落了
                    Box2Map                #将当前移动中的方块贴到背景方块中
                    RandomBox        #产生新的方块
            fi
    }

    #左移一列
    function BoxLeft()
    {
            local x s
            ((x = boxCurX - 1))
            if BoxMove $boxCurY $x
            then
                    s=`DrawCurBox 0`
                    ((boxCurX = x))
                    s=$s`DrawCurBox 1`
                    echo -ne $s
            fi
    }

    #右移一列
    function BoxRight()
    {
            local x s
            ((x = boxCurX + 1))
            if BoxMove $boxCurY $x
            then
                    s=`DrawCurBox 0`
                    ((boxCurX = x))
                    s=$s`DrawCurBox 1`
                    echo -ne $s
            fi
    }


    #下落到底
    function BoxAllDown()
    {
            local k j i x y iDown s
            iDown=$iTrayHeight

            #计算一共需要下落多少行
            for ((j = 0; j < 8; j += 2))
            do
                    ((i = j + 1))
                    ((y = ${boxCur[$j]} + boxCurY))
                    ((x = ${boxCur[$i]} + boxCurX))
                    for ((k = y + 1; k < iTrayHeight; k++))
                    do
                            ((i = k * iTrayWidth + x))
                            if (( ${iMap[$i]} != -1)); then break; fi
                    done
                    ((k -= y + 1))
                    if (( $iDown > $k )); then iDown=$k; fi
            done

            s=`DrawCurBox 0`        #将旧的方块抹去
            ((boxCurY += iDown))
            s=$s`DrawCurBox 1`        #显示新的下落后的方块
            echo -ne $s
            Box2Map                #将当前移动中的方块贴到背景方块中
            RandomBox        #产生新的方块
    }


    #旋转方块
    function BoxRotate()
    {
            local iCount iTestRotate boxTest j i s
            iCount=${countBox[$iBoxCurType]}        #当前的方块经旋转可以产生的样式的数目

            #计算旋转后的新的样式
            ((iTestRotate = iBoxCurRotate + 1))
            if ((iTestRotate >= iCount))
            then
                    ((iTestRotate = 0))
            fi

            #更新到新的样式, 保存老的样式(但不显示)
            for ((j = 0, i = (${offsetBox[$iBoxCurType]} + $iTestRotate) * 8; j < 8; j++, i++))
            do
                    boxTest[$j]=${boxCur[$j]}
                    boxCur[$j]=${box[$i]}
            done

            if BoxMove $boxCurY $boxCurX        #测试旋转后是否有空间放的下
            then
                    #抹去旧的方块
                    for ((j = 0; j < 8; j++))
                    do
                            boxCur[$j]=${boxTest[$j]}
                    done
                    s=`DrawCurBox 0`

                    #画上新的方块
                    for ((j = 0, i = (${offsetBox[$iBoxCurType]} + $iTestRotate) * 8; j < 8; j++, i++))
                    do
                            boxCur[$j]=${box[$i]}
                    done
                    s=$s`DrawCurBox 1`
                    echo -ne $s
                    iBoxCurRotate=$iTestRotate
            else
                    #不能旋转，还是继续使用老的样式
                    for ((j = 0; j < 8; j++))
                    do
                            boxCur[$j]=${boxTest[$j]}
                    done
            fi
    }


    #DrawCurBox(bDraw), 绘制当前移动中的方块, bDraw为1, 画上, bDraw为0, 抹去方块。
    function DrawCurBox()
    {
            local i j t bDraw sBox s
            bDraw=$1

            s=""
            if (( bDraw == 0 ))
            then
                    sBox="\040\040"
            else
                    sBox="[]"
                    s=$s"\033[1m\033[7m\033[3${cBoxCur}m\033[4${cBoxCur}m"
            fi

            for ((j = 0; j < 8; j += 2))
            do
                    ((i = iTrayTop + 1 + ${boxCur[$j]} + boxCurY))
                    ((t = iTrayLeft + 1 + 2 * (boxCurX + ${boxCur[$j + 1]})))
                    #\033[y;xH, 光标到(x, y)处
                    s=$s"\033[${i};${t}H${sBox}"
            done
            s=$s"\033[0m"
            echo -n $s
    }


    #更新新的方块
    function RandomBox()
    {
            local i j t

            #更新当前移动的方块
            iBoxCurType=${iBoxNewType}
            iBoxCurRotate=${iBoxNewRotate}
            cBoxCur=${cBoxNew}
            for ((j = 0; j < ${#boxNew[@]}; j++))
            do
                    boxCur[$j]=${boxNew[$j]}
            done


            #显示当前移动的方块
            if (( ${#boxCur[@]} == 8 ))
            then
                    #计算当前方块该从顶端哪一行"冒"出来
                    for ((j = 0, t = 4; j < 8; j += 2))
                    do
                            if ((${boxCur[$j]} < t)); then t=${boxCur[$j]}; fi
                    done
                    ((boxCurY = -t))
                    for ((j = 1, i = -4, t = 20; j < 8; j += 2))
                    do
                            if ((${boxCur[$j]} > i)); then i=${boxCur[$j]}; fi
                            if ((${boxCur[$j]} < t)); then t=${boxCur[$j]}; fi
                    done
                    ((boxCurX = (iTrayWidth - 1 - i - t) / 2))

                    #显示当前移动的方块
                    echo -ne `DrawCurBox 1`

                    #如果方块一出来就没处放，Game over!
                    if ! BoxMove $boxCurY $boxCurX
                    then
                            kill -$sigExit ${PPID}
                            ShowExit
                    fi
            fi



            #清除右边预显示的方块
            for ((j = 0; j < 4; j++))
            do
                    ((i = iTop + 1 + j))
                    ((t = iLeft + 2 * iTrayWidth + 7))
                    echo -ne "\033[${i};${t}H        "
            done

            #随机产生新的方块
            ((iBoxNewType = RANDOM % ${#offsetBox[@]}))
            ((iBoxNewRotate = RANDOM % ${countBox[$iBoxNewType]}))
            for ((j = 0, i = (${offsetBox[$iBoxNewType]} + $iBoxNewRotate) * 8; j < 8; j++, i++))
            do
                    boxNew[$j]=${box[$i]};
            done

            ((cBoxNew = ${colorTable[RANDOM % ${#colorTable[@]}]}))

            #显示右边预显示的方块
            echo -ne "\033[1m\033[7m\033[3${cBoxNew}m\033[4${cBoxNew}m"
            for ((j = 0; j < 8; j += 2))
            do
                    ((i = iTop + 1 + ${boxNew[$j]}))
                    ((t = iLeft + 2 * iTrayWidth + 7 + 2 * ${boxNew[$j + 1]}))
                    echo -ne "\033[${i};${t}H[]"
            done
            echo -ne "\033[0m"
    }


    #初始绘制
    function InitDraw()
    {
            clear
            RandomBox        #随机产生方块，这时右边预显示窗口中有方快了
            RandomBox        #再随机产生方块，右边预显示窗口中的方块被更新，原先的方块将开始下落
            local i t1 t2 t3

            #显示边框
            echo -ne "\033[1m"
            echo -ne "\033[3${cBorder}m\033[4${cBorder}m"

            ((t2 = iLeft + 1))
            ((t3 = iLeft + iTrayWidth * 2 + 3))
            for ((i = 0; i < iTrayHeight; i++))
            do
                    ((t1 = i + iTop + 2))
                    echo -ne "\033[${t1};${t2}H||"
                    echo -ne "\033[${t1};${t3}H||"
            done

            ((t2 = iTop + iTrayHeight + 2))
            for ((i = 0; i < iTrayWidth + 2; i++))
            do
                    ((t1 = i * 2 + iLeft + 1))
                    echo -ne "\033[${iTrayTop};${t1}H=="
                    echo -ne "\033[${t2};${t1}H=="
            done
            echo -ne "\033[0m"


            #显示"Score"和"Level"字样
            echo -ne "\033[1m"
            ((t1 = iLeft + iTrayWidth * 2 + 7))
            ((t2 = iTop + 10))
            echo -ne "\033[3${cScore}m\033[${t2};${t1}HScore"
            ((t2 = iTop + 11))
            echo -ne "\033[3${cScoreValue}m\033[${t2};${t1}H${iScore}"
            ((t2 = iTop + 13))
            echo -ne "\033[3${cScore}m\033[${t2};${t1}HLevel"
            ((t2 = iTop + 14))
            echo -ne "\033[3${cScoreValue}m\033[${t2};${t1}H${iLevel}"
            echo -ne "\033[0m"
    }


    #退出时显示GameOVer!
    function ShowExit()
    {
            local y
            ((y = iTrayHeight + iTrayTop + 3))
            echo -e "\033[${y};0HGameOver!\033[0m"
            exit
    }


    #显示用法.
    function Usage()
    {
        cat <EOF
        usage: $APP_NAME
        Start tetris game

        -h, --help              display this help
            --version           output version information 
        EOF
    }


    #游戏主程序在这儿开始.
    if [[ "$1" == "-h" || "$1" == "--help" ]]
        then
            Usage
    elif [[ "$1" == "--version" ]]
        then
            echo "$APP_NAME $APP_VERSION"
    elif [[ "$1" == "--show" ]]
        then
            #当发现具有参数--show时，运行显示函数
            RunAsDisplayer
    else
            bash $0 --show&        #以参数--show将本程序再运行一遍
            RunAsKeyReceiver $!        #以上一行产生的进程的进程号作为参数
    fi
